I would interpret the components like:

Holy water (of no specified value - one vial)

OR if that is not available

powdered silver and iron worth 100gp

It looks to me as the intention is to make the spell cheaper and easier to cast for characters with access to holy water.

I would interpret the components like:

Holy water (25 gp - one flask weighing 1 lb from PHB 150)

OR if that is not available

powdered silver and iron worth 100gp

It looks to me as the intention is to make the spell cheaper and easier to cast for characters with access to holy water.